title: Synthesis of new dipyrido-annulated N-heterocyclic carbenes with ortho substituents.
abstract: A method for the introduction of various substituents at the 4 and 8 positions of 2,10-di-tert-butyldipyrido[1,2-c;2',1'-e]imidazolium salts, is described. The new imidazolium salts bearing substituents (R' = Cl, SPh) at the 4 and 8 positions are synthesized in three-step procedures, and carbenes generated from the imidazolium salts can be used to give the corresponding rhodium complexes. The role of the 4,8-substituents can be either bystanders or coordinating ligands according to the nature of the metal moiety.
authors.affiliation: Department of Chemistry, Graduate School of Science, Hiroshima University , 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan.
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Fuku-en
authors.forename: Junki
authors.initials: J
authors.lastname: Yamamoto
authors.forename: Mao
authors.initials: M
authors.lastname: Minoura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kojima
authors.forename: Yohsuke
authors.initials: Y
authors.lastname: Yamamoto